Refrigerating apparatus



May 1935- I E. E. ALLYNE 2,002,426

REFRIGERATIIIIG APPARATUS FilgdFeb. 25, 1932 .2 Sheets-Sheet l INVENTOR ATTORNEY! y 1935- I E. E. ALLYNE Q 2,002,426

REFRIGERATING APPARATUS Filed Feb. 25, 1952 2 Sheets-Sheet 2 INVENTOR- firm/rid M 5 w, 1/;2 Wyn ATTORNEY! Patented May 21, 1935 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates'to refrigerating apparatus of the intermittent absorption type. One object of the invention is to provide a more efiicient heat exchange system for apparatus of this kind,

5 by means of which, during the boilingv operation,

more eflicient rectification and condensation are secured, while during absorption more eflicient circulation of the boiler liquor and a consequent more eflicient absorbing effect are secured.

A further object of the invention is to provide an improved heat transfer device for apparatus of this character, which compels more or'less minute subdivision or breaking up of the stream of gas or liquid, as the case may be, with the possibility of largely increasing the ratio of surface available for heat dissipation to the volume of gas or liquid to be cooled.

A further object of the invention is to provide a heat exchanger of very simple construction but which is very efllcient in operation, and more particularly a heatexchanger involving concentrio tubes together with means for uniformly spacing them apart and at the same time providing tortuous passages in the annular space between them, all as will more fully appear from the following description and the drawings, in which Fig. 1 is anelevation, partly in section, illustrating one suitable embodiment of the invention.

Fig. 2 is a detail sectional plan view, somewhat exaggerated, on the line 2--2, Fig. 1.

Fig. 3 is a view corresponding to Fig. 1 and illustrating modifications.

Fig. 4 is a detail elevation, illustrating still another modification. I

.The apparatus as a whole is of generally well known type suitable for the production of a refrigerating effect by the intermittent absorption principle. Consequently, the entire system for containing the absorbing agent, such as water or the like, and refrigerant, such as ammonia or the like, is sealed against any possible escape, no moving parts extending from the inside to the outside of the apparatus. The apparatus embodies a suitable still-absorber I, a rectifier 2, a condenser 3, and an evaporator 4, interconnected in the order named, although any order of connection operative on intermittent absorption principles is suitable. The refrigerant driven off from the still-absorber during the boiling operation passes by way of an upwardly extending loop 5 to a trap ii provided with a return pipe 1 leading to the loop 8 through which the absorbing agent is circulated for cooling purposes during the absorbing operation. From the trap 6 the distilled gas is led by a pipe 9 to the rectifier 2 provided with a return pipe Hi to the still by way of the trap 6, said rectifier also communicating by a pipe H with the condenser 3, from which the 5 condensate is conducted by pipe l2 to a header l3 and thence by pipe I4 and its branches to the evaporator 4. i5 represents a drain or suck back pipe by which absorbing agent or weak liquor undesirably present or collected in the evaporator 0 is returned from the bottom of the evaporator to the still, said pipe at one point passing through a header iii in the loop 5 to provide the so-called hot spot for heat transfer between loop 5 and the drain pipe I5, while l1 represents a balancl5 ing pipe for returning gas from the header l3 directly to the still in a manner to by-passor prevent return flow through the rectifier and condenser.

During the boiling operation the distilled gas flows by loop 5 to the trap 6, thence by pipe 9 to the rectifier, where any absorbing agent carried over with the gas is collected and returned to the trap from which it flows back to the still. Beyond the rectifier the gaseous refrigerant travels to the condenser, where it is condensed to a liquid, which from time to time is compelled to flow to the evaporator where it is collected through and up to the end of the boiling operation. Upon reversal of the cycle, the heat supply to the still being turned off, the absorption process is initiated and the refrigerating half of the cycle goes on, the gas now distilled in or at the absorber returning to the still by way of the pipe ii for introduction into the stream of absorbing agent flowing through the loop 8, which of course is suitably cooled for producing circulation, such as by beingprovided with heat radiating fins 18, as is usual.

In the present invention either or both of the rectifying and condensing members is of special construction, as now to be described. In the drawings the two members are generally quite similar, so that as to a number of features description of one will suflice for both. Generally speaking, each of the members shown comprises two concentric tubular members, to wit, an outer member 20 and an inner member 2|, which are lengthwise coextensive but which areseparated from each other by a relatively minute gap which, of course, is of uniform annular form when the tubes are concentric. The purpose of this construction is to compel subdivision of the stream of gas or liquid, as the case may be, into a very thin layer to increase the ability to take the heat out of the stream, by providing a very large area or surface very closely contiguous to all parts of the stream of gas or liquid and from which surface the heat is rapidly radiated. This avoids any solid core of gas or liquid which is difficult to cool, as when the material is cooled while passing through a cylindrical pipe or conduit. In practice, for refrigerating purposes, I propose to make this annular passage or channel between the two tubes of the thickness of 3% of an inch, more or less, in the radial dimension, and to make the passage uniform in thickness around the periphery of the tubes any suitable spacing means may be employed. To illustrate, I may wind the outer surface of the inner tube, before the tubes are secured together, with one or more turns of a small wire 40 of approximately the diameter of the space between the tubes, say 3 of an inch. Two pieces of such wire placed from each other and wound separately with the same degree of spirality provide two parallel spiral channels in thespace between the twotubes, as will be readily understood. Such wires therefore not only serve as spacers around the entire periphery, but also as bafiies to compel more or less circuitous flow of the stream through the annular space broken up by the wires into spiral channels. The same effect may be secured by rolling or pressing small ribs in the metal of one of the tubes, as at 40a, and if a baflling effect is not important, these ribs may become simple small teats or projections. The two tubes may be secured and sealed to each other at their opposite ends in any suitable manner, such as by a welding operation, and to insure delivery of material to and its flow from the entire periphery, one or both of the tubes may be provided with beaded end portions providing annular channel 22. These annular channels may be produced by inward beading of the inner tube, as at both ends of the condenser 3; by outward beading of the outer tube, as at the bottom of the rectifier 2; or by both inward beading of the inner tube and. outward beading of the outer tube, as at the top of the rectifier 2. Any of these arrangements may be used at either or both ends of either the rectifier or condenser, and either or both thereof may be provided with spacing wire or other spacing means, as described.

In a rectifier or condenser equipped with two spacing ribs or wires located at 180 from each other, it will of course be understood that the baffling effect is continued through the upper annular channel 22, as shown in somewhat exaggerated form in Fig. 2, as a consequence of which gas delivered from the pipe 9 to the channel 22 is unable to directly travel around the same to the outlet pipe II, but is compelled to travel clear to the bottom of the spirally di vided annular space and thence up again through the other spiral path to the outlet pipe II. The baflies, however, do not extend through the annular channel 22 at the bottom.

Of course, with this heat transfer device formed of two concentric tubes, as described, suitable provision must be made for'the circulation of heat absorbing material in contact with both the'inner surface of the inner tube and the outer surface of the outer tube, because heat is dissipated through both of said surfaces. The rectifier 2 shown in Fig. 1 is a simple plain rectifier exposed to the air both internally and externally and heat dissipation occurs by the fiow of air along both surfaces. The same is true with the rectifier shown in Fig. 3. In the condenser shown in Fig. 3 the outer tube has secured thereto a series of vertically extending thin heat conducting ribs or vanes 24 which provide additional heat dissipating effect, and the interior of the inner tube is open so that a stream of cooling air can flow continuously up through the same.

In the arrangement shown in Fig. 1, the condenser 3, made of two like tubes, is immersed in a water column 25 within a stand pipe 26 closed at top and bottom as shown. This stand pipe is larger than the outer tube 20 so as to provide a layer of water along the exposed surfaces of both the inner and outer tubes. For increasing eificiency on the matter of heat dissipation the stand pipe may be in circulatory communication through the connections 21, 28 with a reservoir or tank 29 for a large body of cooling water and, indeed, if desired, means may be provided for changing the mass of water in the tank 29 and in the stand pipe, where impounded noncirculating water is not suitable. For circulation the tank 29 would of course be connected to a supply of running water and to the sewer. For similar reasons the tank 29 at its upper end may communicate with or be formed as a wide, shallow tray 30 open or exposed to the atmosphere.

With this arrangement, a level of water is maintained in the tray 30 and the evaporation from its exposed surface has the effect of cooling the entire body of water and the cooling effect may be maintained by replenishing the water lost by evaporation.

Where the condenser is in a stand pipe, as in Fig. 1, it operates on the counter flow principle, the refrigerant flowing downwardly and the cooling water flowing upwardly, as will be readily apparent.

Suitable means may also be provided for cooling the condensate collected in the 'condenser 3. Fig. 3 shows the condensing space communicating with the pipe l2 which has one or more turns or coils i 2a passing through or in contact with extensions of some of the fins l8 used to cool the loop 8. During the boiling period, when condensation is occurring in the condenser 3, there is no circulation through the loop 8, so that the fins l8 serve as air cooling means for the condensate passing through the coils [2a of pipe l2. However, when necessary, the pipe I2 may be coiled around a member 32, shown as of pipe form in Fig. 4, said member 32 being connected to a supply of running'water for cooling the condensate passing through pipe l2.

1 also shows the apparatus provided with means for utilizing the water or cooling medium in the stand pipe 26 and tank 29 for assisting in cooling the loop 8 during the absorbing or refrigerating period. In this arrangement, the bottom of the stand pipe is closed by a cap 33 in which is a plug 34 through which extend two pipes 35, 36, opening respectively at low and high levels in the water column and connected by one or more coils or turns 31 lying within open recesses 38 notched in the edges of the heat radiating fins l8, to which they may be secured. This is a convenient arrangement for attaching the coils or turns 31 to the fins l8 with proper heat conducting contact therebetween and with this arrangement, during the absorbing period, when the gas distilled in the evaporator is returning to the still by Way of the by-pass or balancing pipe l'!, the heat of the absorbing agent circulated through the loop 8 is conducted by the fins l8 to the pipe coils 31 to heat the Water therein and thus transfer the heat to the water body for dissipation therefrom in the manner described. In other words, with the mouths of the pipes 35, 36 at low and high levels, the coils 31 by contact with the fins I8 produce a thermo-syphon circulation of the water in the stand pipe for transferring to said water some of the heat of the material in the loop.

In Fig. 1, I have shown a heat conductive connection between the metal of the rectifier and that of the stand pipe 26, the connection consisting of a tubular member 39, made of copper, brass or other heat conducting material and sleeved around a flange 4| at the bottom of the rectifier and a flange 42 on the cap of the stand pipe. This tube may be split and held in place by split clamping collars 43. Its purpose is to make the rectifier more or less self-adjusting to room temperature and the rate of heating up of the rectifier. The sleeve, of course, has air openings H, the total area which is equal tothe cross sectional area of the ir passage through the center of the rectifier. W en the air cooling capacity of the rectifier becomes more or less overtaxed, as it may be during the latter part of a heating period, any tendency toward overload is passed on to the water tank by conduction of some of the superfluous heat through the metal collar from the rectifier to the water in the stand pipe. It is a supplemental cooling means for the rectifier.

The apparatus described is quite eificient in operation and provides for very rapid dissipation of heat energy, with the effect in the rectifier of quickly collecting any liquid absorbing agent which may be carried over during the boiling operation and returning it to the still, while the condenser rapidly dissipates the heat of the gas either to the air, as in Fig. 3, or to the water, as

in Fig. 1, so that condensation occurs readily and with high efllciency, in addition to which the condensate itself is cooled either at the coils l2a, or at the cooler 32, so that it is delivered to the evaporator not much above ordinary room temperature. During the absorbing period the heat of the absorbing agent circulated through the loop may also be conducted quickly to the water body, as in Fig. 1, for promoting absorbing action and consequently securing increased and more emcient refrigeration.

What I claim is:

1. Refrigerating apparatus of the character described, comprising a heat transfer device including two concentric tubes spaced apart and secured to each other at their ends, means for circulating material to be cooled through the annular cavity between said tubes for dissipation of its heat through the surfaces of the two tubes, a receptacle for cooling medium, and a tubular heat conducting member concentric with said tubes forming a connection between the said tubes and the said receptacle and adapted to conduct heat therebetween, said connection having side openings for the admission of cooling medium to the channel within the irmer tube.

2. A refrigerating apparatus of the class described including a rectifier-condenser unit adapted to cool and condense the refrigerating medium, the unit consisting of two sets of concentric, spaced tubes joined at their ends and placed in spaced apart vertical relation, the lower of said tube sets being encased in a chamber in communication with a liquid supply while the upper of said sets is supported on said chamber and is out of contact with said liquid supply.

EDMUND E. AILYNE. 

